Container, particularly for liquefied petroleum gas



A g- 1966 o. J. VAN LEER CONTAINER, PARTICULARLY FOR LIQUEFIED PETROLEUM GAS Filed May 22, 1964 INVENTORI" 0504 J4cau$ 1444 (55? BY 0%, 7 ,m flan/w,

United States Patent 3,269,132 CONTAINER, PARTICULARLY FOR LIQUEFIED PETROLEUM GAS Oscar J. van Leer, Kortenhoef, Netherlands, assignor to Metal Containers Limited, London, England, a British limited-liability company Filed May 22, 1964, Ser. No. 369,552 Claims priority, application Great Britain, May 24, 1963, 20,815/63 Claims. (Cl. 62-45) The present invention relates to a container which is particularly suitable for the packaging, the storage and the transport of liquefied petroleum gas, hereinafter to be referred to as L.P.G., such as, for instance, butane or propane. However, it is to be understood that the use of the container according to the invention is not restricted to the packaging etc. of L.P.G.; on the contrary, the container according to the invention may advantageously be used for other purposes as well.

The conventional containers for L.P.G. have the drawback that if they are superheated, for instance by a fire in the building in which they are positioned, there is a serious danger of explosion. The invention has for an object to provide a container which when being superheated will not explode, or with which the risk of explosion is considerably reduced.

Thereto, the container according to the invention is gas and liquid tight at normal temperatures, but when reaching a predetermined temperature becomes porous so that the gas is enabled to escape in numerous small jets which may catch fire; however, the danger of explosion is eliminated or reduced, since the gas has the possibility to escape and thus will not put the container under abnormal pressure.

The container according to the invention comprises a shell which at least over part of its area is porous and which is provided with an internal lining that is impermeable to gas and liquid at normal temperatures but which disintegrates, creeps, flows plastically, melts, cracks, tears or otherwise becomes leaky when heated to a predetermined temperature.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawing showing a container according to the invention partly in a vertical cross-sectional view and partly in side elevation.

While the invention will be described in connection with a preferred embodiment, it will be understood that I do not intend to limit the invention to that embodiment. On the contrary, I intend to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

Referring to the drawing, there is shown a container generally indicated at 10 and including a shell consisting of an outer wall 11 and an inner wall 12. The two walls have similar shapes and they snugly fit into one another. The shell 11, 12 is porous and it is provided with an internal lining 13 that is impermeable to gas and liquid at normal temperatures but which disintegrates, creeps, flows plastically, melts, cracks or otherwise becomes leaky when heated to a predetermined temperature.

The container is provided with a bottom fitting 14 which together with a retaining ring 15 clasps the edge around a central opening in the outer wall of the container shell.

Similarly, a top fitting 16 is provided, which is adapted to receive, for instance, a screw threaded discharge valve (not shown in the drawing) and which is held in place by means of a retaining ring 17.

In a preferred embodiment of the invention shown in the drawing the outer and the inner walls of the container shell are constituted by filament wound vessels; the total 3,269,132 Patented August 30, 1966 wall thickness of the shell is sufiiciently small to provide for the desired porosity. When winding the resin impregnated or resin moistened filaments or fibres a certain amount of interstices are formed; these might be obturated by a large number of layers being Wound on top of one another. It has been found that the container according to the invention may be sufficiently strong for the purpose it has to serve when the wall thickness is still comparatively small, so that the number of superposed layers is not large enough to close the interstices and the porosity desired in the container according to the invention is thus obtained as an incident of the method of making it.

When the container according to the invention is heated to a temperature above the predetermined one-the container as a whole becomes leaky so that the gas is allowed to escape in numerous jets and does not get the chance to increase the internal pressure in the container to a level where there will be the danger of explosion of the container. The temperature of the environs may rise to a height at which the escaping gas is ignited; yet, the container will not explode but the escaping gas. jets will only burn, thus giving the container the appearance of a St. Elmos fire.

The predetermined temperature at which the lining 13 becomes leaky is preferably over centigrades; when the container is intended to hold propane the temperature referred to is preferably in the order of centigrades; when the container is to hold butane the temperature at which the lining 13 becomes leaky is preferably in the order of centigrades.

I have found that advantageous results are obtained by making the lining of a copolymer of epoxy resin and Thiokol which is a trade name for a synthetic rubber on the base of alkenepolysulfides. Satisfactory results have also been obtained by using polyester, particularly a fiexibilized polyester as internal lining material. Other materials coming into consideration and found to be suitable for the purpose concerned are epoxy/polyester copolymers, a Thiokol monopolymer and synthetic resins including a polyester which at least is partly based on isophthalic acid and/ or adipic acid.

Glycidylether of versatic acid may be added as an antifoam agent. Another additive which has been advantageous results consists of a colloidal silica.

It has been found that the container according to the invention apart from eliminating or at least considerably reducing the danger of explosion has an additional advantage: when a completely or partly filled container according to the invention is dropped the internal lining and/or the inner wall in the event of the shell being constituted by an outer and an inner wall have the tendency to separate from the outer wall; in that case the outer wall being permeable or porous slowly admits ambient air between the two walls and thereby a shock absorbing effect is obtained.

I claim as my invention:

1. A storage container, particularly for liquefied petroleum gas, comprising a shell, said shell constructed from material which is porous over part of its area, and an internal lining positioned adjacent said shell, said internal lining constructed from material which is impermeable to gas and liquid at normal storage temperatures and when heated to a temperature above approximately 100 centigrades becomes leaky whereby the gas is allowed to escape through the leaky portion of the lining and through the porous part of the shell to thus relieve the internal pressure within the container to avoid the danger of explosion of said container.

2. A container as claimed in claim 1 in which said shell is constituted by a filament wound vessel.

3. A container as claimed in claim 1, in which the said shell consists of two filament wound walls having similar shapes and snugly fitting into one another.

4. A container as claimed in claim 1, in which the temperature at which said lining becomes leaky is from approximately 100 to approximately 160 centigrades.

5. A container as claimed in claim 1, in which the material of said internal lining includes a copolymer of epoxy resin and a synthetic rubber on the base of alkenepolysulfides.

6. A container as claimed in claim 1, in which the material of said internal lining includes a monopolymer of alkenepolysulfide.

7. A container as claimed in claim 1, in which the material of said internal lining includes a polyester.

8. A container as claimed in claim 1, in which the material of said internal lining includes an epoxy/ polyester copolymer.

References Cited by the Examiner UNITED STATES PATENTS 2,908,455 10/1959 Hoadley. 3,058,316 10/1962 Toche 62-45 3,181,589 5/1965 Phelps 62-45 X LLOYD L. KING, Primary Examiner. 

1. A STORAGE CONTAINER, PARTICULARLY FOR LIQUEFIED PETROLEUM GAS, COMPRISING A SHELL, SAID SHELL CONSTRUCTED FROM MATERIAL WHICH IS POROUS OVER PART OF ITS AREA, AND AN INTERNAL LINING POSITIONED ADJACENT SAID SHELL, SAID INTERNAL LINING CONSTRUCTED FROM MATERIAL WHICH IS IMPERMEABLE TO GAS AND LIQUID AT NORMAL STORAGE TEMPERATURES AND WHEN HEATED TO A TEMPERATURE ABOVE APPROXIMATELY 100 CENTRIGRADES BECOMES LEAKY WHEREBY THE GAS IS ALLOWED TO ESCAPE THROUGH THE LEAKY PORTION OF THE LINING AND THROUGH THE POROUS PART OF THE SHELL TO THUS RELIEVE THE INTERNAL PRESSURE WITHIN THE CONTAINER TO AVOID THE DANGER OF EXPLOSION OF SAID CONTAINER. 